QGIS – Displaying WGS 84 (EPSG:4326) Coordinate Grid Over EPSG:3857 Map

Question

Is there a way to either display a grid with WGS 84 decimal degrees over a map that is in EPSG:3857, something like OpenStreetMap? I've tried changing the project's the map's and the grid's CRS but I either get a map that's stretched and has wrong coordinates, no map or when I tried changing grid CRS no grid at all.

Also, what's with the coordinates being reversed in QGIS?

Answer 1

There are at least two approaches to create a grid: in the QGIS main window, creating a vector (line) layer or in the print composer. Normally, you should stick to the last solution. However, if for some reason you need it as a separate layer, I describe both approaches:

QGIS main map canvas

To add a grid in the QGIS main windon on the map canvas, go to Menu Vector > Research Tools > Create Grid. Use Line Grid Type, set Grid CRS to EPSG:4326 and define a Grid extent consisting of integer numbers only - like -189,189,-134,128 [EPSG:4326]. For Horizontal/Vertical spacing use an integer value like 1 as well for 1 degrees intervals.

Depending on the project CRS, you should densify the grid lines to get a correct grid.

Print composer

To add a grid in the print composer, on the map element's Item Properties, expand the section Grid click the green plus to create a new grid and make the relevant settings: